To celotex or not to celotex?

[Mikejf]

You should lay a vapour control layer over the celotex. To quote from Celotex's installatiion guidelines based on over slab installation...

"Lay a polythene vapour control layer over the insulation to minimise the risk of condensation and to prevent liquid screed migration"

Just go to Celotex's website and there are technical data on how thick the insulation should be. There is a calculation you can do based on the area of the extension and the exposed internal perimeter.

You should be looking to acheive a U-value of 0.22 but as its a conservatory (I assume you have kept it seperate from the main dwelling by external doors) then it doesn't require regs and therefore you don't have to stick to the required U-value, although you should where possible.

Mike

 

[noseall]

You should be looking to acheive a U-value of 0.22 but as its a conservatory (I assume you have kept it seperate from the main dwelling by external doors) then it doesn't require regs and therefore you don't have to stick to the required U-value, although you should where possible.

Precisely.

 

[dch]

yeah it is seperate from the house and I understand where ya coming from with it being just a conservatory to be honest I was just gona put a slab in when I first started out but was told that the UFH would benifit having the insulation under it but thats not going in now but still going to use it as UFH may be added at a later date.

I know its the regs in an extention or new build regarding the insulation but when did all this come into play with building regs an stuff with insulation and u values having to be there and can they honestly tell if they come to inspect it? I know that question is a bit off topic but interested to know

 

[noseall]

I know its the regs in an extention or new build regarding the insulation but when did all this come into play with building regs an stuff with insulation and u values having to be there and can they honestly tell if they come to inspect it? I know that question is a bit off topic but interested to know

Part of the inspection process is to inspect the oversite of any regulated extension or new build.

This involves peeling back any dpm material, exposing the insulation and the removal of a piece of insulation so that the bco can get a look at the product etc.

Oversite insulation has been around for about 25 years, (probably ) and has always been inspected as far as i know.

The science of u and r values has been around for a while and being able to measure thermal resistance is a good way of being able to indicate to designers/architects/builders of the products required to stay within a certain thermal regulation.

When i first started, wall cavities were 50mm, floor insulation did not exist and loft insulation was 100mm. Air leakage was what builders did on a Friday morning!

 

[ban-all-sheds]

If you have any heating at all in the conservatory then the energy efficiency requirements of the Building Regulations apply to it, which will include the U value of the floor.

 

[noseall]

If you have any heating at all in the conservatory then the energy efficiency requirements of the Building Regulations apply to it

No they don't.

 

[dch]

If you have any heating at all in the conservatory then the energy efficiency requirements of the Building Regulations apply to it, which will include the U value of the floor.[/quote

The only regs I know about is that if you fit a radiator then it has to be controllable by its own thermostat, then again if there is no building regs to stick to as its a conservatory no one knows what you do in there anyway.